A Geometry Nodes setup depositing points in a particular location with surface constrained movement. Then, you can instance whatever object you wish on these points. 

The setup comes with explanations and labels.

Simplified, step-by-step setups included for ease-of-read and reuse.

(The scene is an example of the use of this setup. The points (and objects instanced on them) can be deposited an moved on any surface -simulating crystal deposit, dust, molecular sutructures and so on)

Video demo here, here and here.

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NOTE

-(Since it is a concept demonstration, it is kept as simple as possible.) The GeoNodes trees are kept clean for easier readability and have detailed explanations. Everything is built from the base. The point of these setups is to provide a base core of the concept, node from node, instead of contracting all into node groups with exposed settings, which makes everything harder to read and dissect.

You can embellish, refine as you wish based on the core or realize your own ideas.

- Read the text description, it has a lot of useful info !